Vehicle guard rail



Dec. 24, 1968 .1. H. GRAY VEHICLE GUARD RAIL 2 Sheets-Sheet l Filed May25. 1967 INVENTOR. JAMES HARVEY GRAY BY/vydgaad) m H 1.' TQRNEYa Y Dec.24, 1968 J. H. GRAY VEHICLE: GUARD RAIL 2 Sheets-Sheet 2 Filed May 25.1957 .,x... w 1 Il bwvvts,...

i rm, f N Y c v u m n HTToRNEY United States Patent Oice 3,417,965Patented Dec. 24, 1968 3,417,965 VEHICLE GUARD RAIL James H. Gray, 75840Altamira Drive, Palm Desert, Calif. 92260 Filed May 25, 1967, Ser. No.641,244 3 Claims. (Cl. 256 13.1)

ABSTRACT F THE DISCLOSURE A vehicle guard rail assembly particularly forerection alongside a highway or between divided highways which iscapable of positively but yieldably arresting the lateral travel ofvehicles which hit it, and support their return to the traic lane. Theguard rail is pivotally supported, and a torque tube resists pivotingupon impact of a vehicle.

BRIEF SUMMARY OF THE INVENTION In general, the guard rail assembly ofthis invention comprises a plurality of inclined arm members pivotallymounted on anchor posts driven into the ground. The anchor posts arespaced along the side of a highway, or on a median strip. Anyconventional type of railing or steel cable can 'be attached to theextended arms of the assemblies to face the highway. The rail is thepart of the assembly that is struck by the vehicle. Under impact loadsthe rail pivots vertically on the assembly, permitting a torque tube,which is connected to each inclined arm member, to twist and resistpivotal movement of the inclined arm.

By contrast, the use of springs, hydraulic shock absorbers, or similardevices, on each arm supporting the rail will have the effect ofconcentrating and localizing the impact loads instead of giving them thespanwise distribution achieved by the torque tube. In this case theindividual arms and rail segments are subject to greater stresses ashigher loads are put on the posts. Under such conditions the rail is farmore apt to exceed its elastic limits, and pocket, thus permitting thefront wheel of the vehicle to come in contact with a post. In such casesthe car will probably spin and possibly roll. As the vehicle leaves therail in this manner a following car collision is a high probability inheavy trailic.

The use of springs, or similar devices, on the individual arms willrequire a rail of impractical weight and rigidity to achieve theperformance obtainable with standard rail and torque tube. With thelocally concentrated energy storage a vicious rebound may be expected.In the event of post damage and distortion, a compressed spring may bereleased from its seating and become an extremely dangerous projectile.

Hydraulic systems would be safer than springs, but less reliable becauseof temperature effects on the uid. Under extreme winter conditions theymay fail to yield due to very high viscosity. Conversely, the lowviscosity caused by high summer temperatures may prevent them fromabsorbing a significant measure of the impact energy.

Such systems would present prohibitive maintenance problems, in additionto excessive initial costs.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE l is a generally diagrammaticaltop plan view showing two spans of the guard rail assembly;

FIGURE 2 .is a similar front elevation view of the guard rail assemblyof FIGURE l;

FIGURE 3 is a similar rear elevation view of two spans of the guard railassembly of FIGURE l;

FIGURE 4 is a fragmentary front elevation view on an enlarged scale ofthe guard rail and post construction;

FIGURE 5 is a view partly in section taken along the line 5 5 of FIGURE4, with the guard rail assembly in normal position;

FIGURE 6 is a view in section taken along the line 6 6 of FIGURE 4;

FIGURE 7 is an enlarged fragmentary top plan view as viewed from aboveFIGURE 4;

FIGURE 8 is a view similar to FIGURE 5, taken on the line 8 8 of FIGURE2;

FIGURE 9 is a view in section to that of FIGURE 6 but showing the guardrail in a partially yielding position under impact with a vehicle;

FIGURE 10 is a view in section similar to that of FIGURE 8, but showingthe guard rail in a fully yielding position; and

FIGURE 1l is a view in section similar to that of FIG- URE 6, butshowing a modiication of the invention.

DETAILED DESCRIPTION OF THE INVENTION The guard rail assembly 20, asshown in FIGURES 1 3, comprises a rail 21 supported from a plurality ofpost assemblies 22. Each post assembly 22 is constructed of a pluralityof parts which will be described hereinafter.

The rail 21 comprises a channel member which extends along the side of ahighway. The `channel member has the W-beam cross-sectional shapegenerally illustrated in FIGURE 5 (as two convex or C-shaped portions 24and 25 joined together by a narrow ilat strip portion 26). The rail 21`may be of other shapes.

The bases 27 of a plurality of U-brackets 28 are fastened by bolts 29 tothe strip portions 26. The U-'brackets 28 have spaced parallel sideflanges 30 and 31.

For each post assembly y22, there is a post 35 driven into the ground Galongside a highway. The posts 35 are positioned parallel to thehighway.

Each post assembly 22 also includes -a downwardly extending, inclinedH-beam member 38, provided with anges 39 and 40. The downwardlyextending H-beam flanges 39 and 40 have lower ends 41 and 42 porjectingbelow the ground into which the posts 35 are driven. A metal U-shapedstrap 43 is -wrapped about the post 35 if a wood -post is used (notrequired on steel posts), and the plates 39 and 40 are pivotally mountedto the post 35, with the U-shaped strap 43 around the back and sides ofthe post and between the H-beam anges and the post.

The pivotal mount for the H-beam member 38 comprises one end 44 of atension-torsion rod 45. The end 44 of a tension-torsion rod 45. The endof the rod 45 has a nut 46 threaded against and welded to the anges 41or 42 and welded to the rod 45. The other end 48 of the rod 45 extendsthrough the side anges 30 and 31 of the bracket 28 and through theflanges 39 and 40 of the i11- clined H-beam member 38 of the next postassembly. A nut 49 is threaded onto the end 48 of the rod 45, and therod end 48 is welded to the side flanges 30 and 31 to enable the rod 45to function both as a tension and torsion member and to hold the rail ina generally vertical position. Thus the rods 45 act as tension membersto keep the post assemblies 22 from bending over or rotatinghorizontally in the direction of travel of an automobile upon impact bya vehicle. Since each rod 45 is welded to the anges 39 and 40, the rodalso provides torsion resistance to swinging of an inclined H-beammember 38 upon impact. With respect to assemblies 22 that have the end44 of a rod 45 anchored in the post 35, the guard rail 21 is secured tothe member 38 by means of a headed bolt 47 that extends through the sideflanges of a bracket 28 and the flanges 39 and 40 of said arm member. Alock washer and nut are applied to the projecting end of the bolt, asshown in FIGURES 5 and 7. With respect to the post assemblies 22 that donot have the end 44 of a rod 45 anchored in the post 35, the lower endportion of the member 38 is pivot- 3 ally secured to the post by asimilar bolt 47 that extends through the post and the flanges 39 and 40of said arm member. A lock washer and nut are applied to the projectingend of the bolt, as shown in FIGURE 8.

An elongated steel torque tube 55 of circular crosssection is fastenedto the inclined members 38 by a plurality of U-bolts 56. The torque tube55 has flattened sections 57 where it is connected by the U-bolts 56 sothat, when the nuts 58 are turned to tighten the U-bolts, the torquetube 55 cannot rotate relative to the inclined members 38. If the posts3S are Wood, they have depressions 59 in them for accommodating the nuts58 and ends of the U-bolts 56. If steel H-beam posts are used, suchclearance is provided by the shape -of the post.

FIGURE 9 shows the partially pivoted position of the guard rail assemblyupon impact with a vehicle, and FIG- URE 10 shows the fully pivotedposition. The vehicle strikes the rail 21 as the vehicle veers off thehighway. However, the vehicle instead of meeting a semi-rigid or rigidunyielding barrier, is met with a somewhat yielding barrier. As thevehicle strikes the rail 21, the inclined arms 38 near the point ofimpact pivot toward the position shown in FIGURE 9, but the weight andinertia of inclined members 38, 21 and 55 remote from the impact areakeeps them in the inclined positions shown in FIG- URE 6, therebycausing twisting of the torque tube 55 and the tension-torsion rods 45.The torque tube 55 and the rods 45 yield, permitting the inclinedmembers near the point of impact to pivot toward the position shown inFIGURE 8, but the resistanceto yielding is such that the barrier pivotsto the position shown in FIGURE 9 with absorption of energy by thetorque tube 55 and rod 45 and consequent reduction of shock forces. Asthe members 38 pivot, the rail 21 remains in a vertical position asillustrated in FIGURE 10, against the vertical side of the vehicle andplaces a torsion load on the rod 45. The web 50 between the flanges 39and 40 of the H-beam member 38 has a lower end 51 separated from theflanges and bent at 45 and welded back on the flanges, acting as a stopto normally hold the inclined member 38 at a 45 incline relative to thepost 35.

When the post assembly 22 is in the position illustrated in FIGURE 6,the lower end 51 of the downwardly extending member 50 of each postassembly 22 is positioned against the post 35. The weight of theinclined members 38 and the rail 21 biases the post assemblies 22 towardthis position.

From the foregoing, it is apparent that the use of torque tubes asenergy absorbing elements in the design of energy absorbing guard railsystems has several advantages. The torque tube produces a spanwisedistribution of energy over several post assemblies in either directionfrom the point of impact. This lateral energy distribution results in auniform curvature of the rail and tube that progresses, wave-like, withthe vehicle, the point of contact remaining at the center of thecurvature until contact is broken.

Interaction of the inclined members 38 permits the rail to yield as asmooth continuously curving surface, turning and guiding the vehicleback toward its proper traiic lane. This is accomplished without severenegative acceleration and with minimum transverse accelerations.

The spanwise distribution of energy also tends to prevent the rail frombending beyond its elastic limits and consequent permanent distortion.

As energy is absorbed by the torque tube 55, it is stored throughout itseiective length and, unless major damage has been incurred, will restorethe rail to its normal static position as contact with the vehicle isbroken. The energy is stored over a suicient length, or volume, of steelthat there is little possibility of unacceptable rebound.

The torque tube 55 performs a dual purpose by providing additionalsafety in an energy absorbing guard rail system. The rail 21, beingpivotally mounted on the inclined members 38, will rise as it recedesunder impact. For conventional sized cars this is an advantage inpreventing their jumping or rolling over the rail, a factor that isparticularly necessary on median installations. In the case of smallcompact cars, however, the increase in clearance below the rail willpermit them to pass under the rail, with usually fatal results to theoccupants. The torque tube, in addition to its work in absorption anddissipation of energy, also functions as a rubbing rail, effectivelypreventing underpassing of small vehicles.

FIGURE 11 shows a slight modification of the invention. Here, the lowerend 62 of the H-beam arm web 50 is extended well into the ground G.Also, the plates 39 and 40 have lower vertical extensions 63 extendinginto the ground and welded to the side edges of the lower end 62 of theplate 50. With these extensions into the ground, further resistance topivoting of the inclined members 38 is provided.

Various changes and modifications may be made within the purview of thisinvention as will be readily apparent to those skilled in the art. Suchchanges and modiiications are within the scope and teaching of thisinvention as defined by the claims appended hereto.

What is claimed is:

1. A vehicle guard rail for erection alongside a highway comprising aplurality of posts adapted to be driven into the ground alongside thehighway, an arm pivotally supported by each post, an elongated torquetube means, means for connecting the torque tube means to the arms andlocking the torque tube means against rotation relative to the arms,whereby pivoting of an arm relative to other arms requires twisting ofthe torque tube means, `a guard rail strung between the arms, means forconnecting the guard rail to the arms for free pivotal movements of theguard rail relative to the arms.

2. The vehicle guard rail of claim 1 including rod means connectedbetween the lower end of one arm and the upper end of an adjacent arm toprevent the arms from being bent in directions longitudinal of the guardrails when hit by a vehicle.

3. The vehicle guard rail of claim 1 wherein the torque tube comprises asteel tube of circular cross-section to provide a spanwise distributionof energy and a smooth curvature of the guard rail under impact andprolonged loading.

References Cited UNITED STATES PATENTS 2,227,958 1/1941 Camp 25613.13,284,054 11/1966 St. Pierre 256-13.1

DAVID I. WILLIAMOWSKY, vPrimary Examiner.

DENNIS L. TAYLOR, Assistant Examiner.

